Environmental enrichment has been shown to have a positive impact on cognitive function such as in ameliorating cognitive decline in various animal models. Enriching an environment can be accomplished in a variety of ways including, but not limited to, the introduction of various objects, sounds, smells, colors, animals, etc. Thousands of research papers reaching this conclusion have been published and the cognitive benefits have been shown to reduce or overcome animal models of human neurological disorders such as Alzheimer's disease, memory loss, vascular dementia, neuronal death in aging, traumatic brain injury, head injury, Parkinson's disease, seizures, stroke, multiple sclerosis, anxiety, autism, ADHD, Huntington's disease, Down Syndrome, stress, depression, cerebral palsy, chemo-brain, schizophrenia, prenatal alcohol syndrome, lead exposure, addiction and cancer, to name a few. Noticeable behavioral changes have been observed in children with autism after as little as six months of environmental enrichment exercises.
Of the various stimulants used in environmental enrichments, it has been found that cognition is strongly associate with olfaction. Olfaction is the only sense that has a large, direct pathway to the cognitive and emotional areas of the brain. Loss of olfaction precedes the memory loss from aging and from all forms of dementia. Olfactory loss triggers a massive loss of neurons in the brain. After the age of 50, it has been found that olfactory ability accurately predicts all-cause mortality within the next five years.
Biologically, olfactory stimulation activates the entorhinal cortex. The entorhinal cortex diminishes with age and other factors such as Alzheimer's and other forms of dementia. As the entorhinal cortex diminishes, it releases the dentate gyrus and CA3 (hippocampal subfields) from inhibition, thereby interfering with memory. Thus, a restoration of olfaction should increase neurogenesis and/or neural complexity in the entorhinal cortex, thereby normalizing dentate/CA3 activity and restoring memory.
Interventions based on environmental enrichment can be expensive or difficult to maintain, as in the case of exercise. Currently, there is a lack of environmental enrichment modalities that effectively improve cognitive function and memory while being low cost, and easy to use or maintain. More specifically, there is a lack of environmental enrichment modalities that exploits the strong association that olfaction has with the cognitive and emotional areas of the brain.